Carbon suboxide

Carbon suboxide
Names
	Preferred IUPAC name Propa-1,2-diene-1,3-dione
Identifiers
CAS Number	504-64-3 ;
3D model (JSmol)	Interactive image;
ChEBI	CHEBI:30086 ;
ChemSpider	120106 ;
MeSH	Carbon+suboxide
PubChem CID	136332;
UNII	9M2M4H5WEJ ;
CompTox Dashboard (EPA)	DTXSID70198443 ;
	show InChI
	show SMILES
Properties
Chemical formula	C3O2
Molar mass	68.031 g·mol−1
Appearance	colorless gas
Odor	strong, pungent odor
Density	3.0 kg/m3, gas 1.114 g/cm3, liquid
Melting point	−111.3 °C (−168.3 °F; 161.8 K)
Boiling point	6.8 °C (44.2 °F; 279.9 K)
Solubility in water	reacts
Solubility	soluble in 1,4-dioxane, ether, xylene, CS2, tetrahydrofuran
Refractive index (nD)	1.4538 (6 °C)
Dipole moment	0 D
Structure
Crystal structure	rhombic
Molecular shape	quasilinear (phase dependent)
Thermochemistry
Heat capacity (C)	66.99 J/mol K
Std molar; entropy (So298)	276.1 J/mol K
Std enthalpy of; formation (ΔfH⦵298)	−93.6 kJ/mol
Related compounds
Related oxides	carbon dioxide; carbon monoxide; dicarbon monoxide
Related compounds	carbon subsulfide; carbon subnitride
	Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
	(what is ?)
	Infobox references

Carbon suboxide, or tricarbon dioxide, is an oxide of carbon with chemical formula C
3O
2 or O=C=C=C=O. Its four cumulative double bonds make it a cumulene. It is one of the stable members of the series of linear oxocarbons O=C_n=O, which also includes carbon dioxide (CO₂) and pentacarbon dioxide (C
5O
2). Although if carefully purified it can exist at room temperature in the dark without decomposing, it will polymerize under certain conditions.

The substance was discovered in 1873 by Benjamin Brodie by subjecting carbon monoxide to an electric current. He claimed that the product was part of a series of "oxycarbons" with formulas C_x+1O_x, namely C₂O, C
3O
2, C₄O₃, C
5O
4, ..., and to have identified the last two;^[3]^[4] however, only C
3O
2 is known. In 1891 Marcellin Berthelot observed that heating pure carbon monoxide at about 550 °C created small amounts of carbon dioxide but no trace of carbon, and assumed that a carbon-rich oxide was created instead, which he named "sub-oxide". He assumed it was the same product obtained by electric discharge and proposed the formula C
2O.^[5] Otto Diels later stated that the more organic names dicarbonylmethane and dioxallene were also correct.

It is commonly described as an oily liquid or gas at room temperature with an extremely noxious odor.^[6]

Synthesis[]

It is synthesized by warming a dry mixture of phosphorus pentoxide (P
4O
10) and malonic acid or its esters.^[7] Therefore, it can be also considered as the anhydride of malonic anhydride, i.e. the "second anhydride" of malonic acid.^[8]

Several other ways for synthesis and reactions of carbon suboxide can be found in a review from 1930 by Reyerson.^[6]

Polymerization[]

Carbon suboxide polymerizes spontaneously to a red, yellow, or black solid. The structure is postulated to be poly(α-pyronic), similar to the structure in 2-pyrone (α-pyrone).^[9]^[10] The number of monomers in the polymers is variable (see Oxocarbon#Polymeric carbon oxides). In 1969, it was hypothesized that the color of the Martian surface was caused by this compound; this was disproved by the Viking Mars probes (the red color is instead due to iron oxide).^[11]

Uses[]

Carbon suboxide is used in the preparation of malonates; and as an auxiliary to improve the dye affinity of furs.

Biological role[]

Those are 6- or 8-ring macrocyclic polymers of carbon suboxide that were found in living organisms. They are acting as an endogenous digoxin-like Na+/K+-ATP-ase and Ca-dependent ATP-ase inhibitors, endogenous natriuretics, antioxidants and antihypertensives

Carbon suboxide, C₃O₂, can be produced in small amounts in any biochemical process that normally produces carbon monoxide, CO, for example, during heme oxidation by heme oxygenase-1. It can also be formed from malonic acid. It has been shown that carbon suboxide in an organism can quickly polymerize into macrocyclic polycarbon structures with the common formula (C
3O
2)_n (mostly (C
3O
2)
6 and (C
3O
2)
8), and that those macrocyclic compounds are potent inhibitors of Na⁺/K⁺-ATP-ase and Ca-dependent ATP-ase, and have digoxin-like physiological properties and natriuretic and antihypertensive actions. Those macrocyclic carbon suboxide polymer compounds are thought to be endogenous digoxin-like regulators of Na⁺/K⁺-ATP-ases and Ca-dependent ATP-ases, and endogenous natriuretics and antihypertensives.^[12]^[13]^[14] Other than that, some authors think also that those macrocyclic compounds of carbon suboxide can possibly diminish free radical formation and oxidative stress and play a role in endogenous anticancer protective mechanisms, for example in the retina.^[15]

Structure and bonding[]

The structure of carbon suboxide has been the subject of experiments and computations since the 1970s. The central issue is the question of whether the molecule is linear or bent (i.e., whether ${\ce {\theta _{C2}=\angle C1C2C3\ {\overset {?}{=}}\ 180\!^{\circ }}}$ ). Studies general agree that the molecule is highly non-rigid, with a very shallow barrier to bending. According to one study, the molecular geometry is described by a double-well potential with a minimum at θ_C₂ ~ 160°, an inversion barrier of 20 cm⁻¹ (0.057 kcal/mol), and a total energy change of 80 cm⁻¹ (0.23 kcal/mol) for 140° ≤ θ_C₂ ≤ 180°.^[16] The small energetic barrier to bending is around the same order of magnitude as the vibrational zero-point energy. Therefore, the molecule is best described as quasilinear. While infrared^[17] and electron diffraction^[18] studies have indicated that C
3O
2 has a bent structure in the gas phase, the compound was found to possess at least an average linear geometry in the solid phase by X-ray crystallography, although the large thermal ellipsoids of the oxygen atoms and C₂ have been interpreted to be consistent with rapid bending (minimum θ_C₂ ~ 170°), even in the solid state.^[19]

A heterocumulene resonance form of carbon suboxide based on minimization of formal charges does not readily explain the molecule's non-rigidity and deviation from linearity. To account for the quasilinear structure of carbon suboxide, Frenking has proposed that carbon suboxide be regarded as a "coordination complex" of carbon(0) bearing two carbonyl ligands and two lone pairs: ${\textstyle {\ce {OC:->{\overset {..}{{\underset {..}{C}}}}<-:CO}}}$ .^[20] However, the contribution of dative bonding in C
3O
2 and similar species has been criticized as chemically unreasonable by others.^[21]

References[]

^ "Carbon Suboxide". WebElements Periodic Table. Retrieved 19 Feb 2019.
^ Weast RC, Astle MJ, eds. (1983). CRC Handbook of Chemistry and Physics (64th ed.). Boca Raton: CRC Press. p. B-82. ISBN 9780849304637.
^ Brodie BC (1873). "Note on the Synthesis of Marsh-Gas and Formic Acid, and on the Electric Decomposition of Carbonic Oxide". Proc. Royal Soc. Lond. 21 (139–147): 245–247. doi:10.1098/rspl.1872.0052. JSTOR 113037. When pure and dry carbonic oxide [=carbon monoxide] is circulated through the induction-tube, and there submitted to the action of electricity, a decomposition of the gas occurs [...] Carbonic acid [=carbon dioxide] is formed, and simultaneously with its formation a solid deposit may be observed in the induction-tube. This deposit appears as a transparent film of a red-brown color, lining the walls of the tube. It is perfectly soluble in water, which is strongly colored by it. The solution has an intensely acid reaction. The solid deposit, in the dry condition before it has been in contact with the water, is an oxide of carbon.
^ Brodie BC (1873). "Ueber eine Synthese von Sumpfgas und Ameisensäure und die electrische Zersetzung des Kohlenoxyds". Liebigs Ann. 169 (1–2): 270–271. doi:10.1002/jlac.18731690119.
^ Berthelot M (1891). "Action de la chaleur sur l'oxyde de carbone". Annales de Chimie et de Physique. 6 (24): 126–132. Archived from the original on 17 February 2012. Retrieved 21 Feb 2007.
^ Jump up to: ^a ^b Reyerson LH, Kobe K (1930). "Carbon Suboxide". Chem. Rev. 7 (4): 479–492. doi:10.1021/cr60028a002.
^ Diels O, Wolf B (1906). "Ueber das Kohlensuboxyd. I". Chem. Ber. 39: 689–697. doi:10.1002/cber.190603901103.
^ Perks HM, Liebman JF (2000). "Paradigms and Paradoxes: Aspects of the Energetics of Carboxylic Acids and Their Anhydrides". Structural Chemistry. 11 (4): 265–269. doi:10.1023/A:1009270411806. S2CID 92816468.
^ Ballauff M, Li L, Rosenfeldt S, et al. (2004). "Analysis of Poly(carbon suboxide) by Small-Angle X-ray Scattering". Angewandte Chemie International Edition. 43 (43): 5843–5846. doi:10.1002/anie.200460263. PMID 15523711.
^ Ellern A, Drews T, Seppelt K (2001). "The Structure of Carbon Suboxide, C
3O
2, in the Solid State". Z. Anorg. Allg. Chem. 627 (1): 73–76. doi:10.1002/1521-3749(200101)627:1<73::AID-ZAAC73>3.0.CO;2-A.
^ Plummer WT, Carsont RK (1969). "Mars: Is the Surface Colored by Carbon Suboxide?". Science. 166 (3909): 1141–1142. doi:10.1126/science.166.3909.1141. PMID 17775571.
^ Kerek F (2000). "The structure of the digitalislike and natriuretic factors identified as macrocyclic derivatives of the inorganic carbon suboxide". Hypertension Research. 23 (Suppl S33): S33–38. doi:10.1291/hypres.23.Supplement_S33. PMID 11016817.
^ Stimac R, Kerek F, Apell HJ (2003). "Macrocyclic carbon suboxide oligomers as potent inhibitors of the Na,K-ATPase". Ann. N. Y. Acad. Sci. 986: 327–329. doi:10.1111/j.1749-6632.2003.tb07204.x. PMID 12763840.
^ Kerek F, Stimac R, Apell HJ, et al. (2002). "Characterization of the macrocyclic carbon suboxide factors as potent Na,K-ATPase and SR Ca-ATPase inhibitors". Biochimica et Biophysica Acta (BBA) - Biomembranes. 1567 (1–2): 213–220. doi:10.1016/S0005-2736(02)00609-0. PMID 12488055.
^ Tubaro E (1966). "Carbon suboxide, the probable precursor of an antitumor cellular substance: retina". Bollettino Chimico Farmaceutico (in Italian). 105 (6): 415–416. PMID 6005012.
^ Brown RD (1993). "Structural Information on Large Amplitude Motions". In Laane J, Dakkouri M, Veken Bv, et al. (eds.). Structures and Conformations of Non-Rigid Molecules. NATO ASI Series. 410. Springer Netherlands. pp. 99–112. doi:10.1007/978-94-011-2074-6_5. ISBN 9789401049207.
^ Jensen P, Johns JW (1986). "The infrared spectrum of carbon suboxide in the ν6 fundamental region: Experimental observation and semirigid bender analysis". J. Mol. Spectrosc. 118 (1): 248–266. doi:10.1016/0022-2852(86)90239-0.
^ Clark A (1970). "The potential function for the CCC bending in carbon suboxide". Chem. Phys. Lett. 6 (5): 452–456. doi:10.1016/0009-2614(70)85190-9.
^ Ellern A, Drews T, Seppelt K (2001). "The Structure of Carbon Suboxide, C
3O
2, in the Solid State". Z. Anorg. Allg. Chem. 627 (1): 73–76. doi:10.1002/1521-3749(200101)627:1<73::aid-zaac73>3.0.co;2-a. ISSN 1521-3749.
^ Frenking G, Tonner R (2009). "Divalent carbon(0) compounds". Pure Appl. Chem. 81 (4): 597–614. doi:10.1351/pac-con-08-11-03. ISSN 1365-3075. S2CID 98257123.
^ Himmel D, Krossing I, Schnepf A (2014). "Dative Bonds in Main-Group Compounds: A Case for Fewer Arrows!". Angewandte Chemie International Edition. 53 (2): 370–374. doi:10.1002/anie.201300461. ISSN 1521-3773. PMID 24243854.

External links[]

WebElements page on compound's properties

[1] "Carbon Suboxide". WebElements Periodic Table. Retrieved 19 Feb 2019.

[2] Weast RC, Astle MJ, eds. (1983). CRC Handbook of Chemistry and Physics (64th ed.). Boca Raton: CRC Press. p. B-82. ISBN 9780849304637.

[3] Brodie BC (1873). "Note on the Synthesis of Marsh-Gas and Formic Acid, and on the Electric Decomposition of Carbonic Oxide". Proc. Royal Soc. Lond. 21 (139–147): 245–247. doi:10.1098/rspl.1872.0052. JSTOR 113037. When pure and dry carbonic oxide [=carbon monoxide] is circulated through the induction-tube, and there submitted to the action of electricity, a decomposition of the gas occurs [...] Carbonic acid [=carbon dioxide] is formed, and simultaneously with its formation a solid deposit may be observed in the induction-tube. This deposit appears as a transparent film of a red-brown color, lining the walls of the tube. It is perfectly soluble in water, which is strongly colored by it. The solution has an intensely acid reaction. The solid deposit, in the dry condition before it has been in contact with the water, is an oxide of carbon.

[4] Brodie BC (1873). "Ueber eine Synthese von Sumpfgas und Ameisensäure und die electrische Zersetzung des Kohlenoxyds". Liebigs Ann. 169 (1–2): 270–271. doi:10.1002/jlac.18731690119.

[5] Berthelot M (1891). "Action de la chaleur sur l'oxyde de carbone". Annales de Chimie et de Physique. 6 (24): 126–132. Archived from the original on 17 February 2012. Retrieved 21 Feb 2007.

[:0-6] Jump up to: ^a ^b Reyerson LH, Kobe K (1930). "Carbon Suboxide". Chem. Rev. 7 (4): 479–492. doi:10.1021/cr60028a002.

[7] Diels O, Wolf B (1906). "Ueber das Kohlensuboxyd. I". Chem. Ber. 39: 689–697. doi:10.1002/cber.190603901103.

[8] Perks HM, Liebman JF (2000). "Paradigms and Paradoxes: Aspects of the Energetics of Carboxylic Acids and Their Anhydrides". Structural Chemistry. 11 (4): 265–269. doi:10.1023/A:1009270411806. S2CID 92816468.

[9] Ballauff M, Li L, Rosenfeldt S, et al. (2004). "Analysis of Poly(carbon suboxide) by Small-Angle X-ray Scattering". Angewandte Chemie International Edition. 43 (43): 5843–5846. doi:10.1002/anie.200460263. PMID 15523711.

[10] Ellern A, Drews T, Seppelt K (2001). "The Structure of Carbon Suboxide, C
3O
2, in the Solid State". Z. Anorg. Allg. Chem. 627 (1): 73–76. doi:10.1002/1521-3749(200101)627:1<73::AID-ZAAC73>3.0.CO;2-A.

[11] Plummer WT, Carsont RK (1969). "Mars: Is the Surface Colored by Carbon Suboxide?". Science. 166 (3909): 1141–1142. doi:10.1126/science.166.3909.1141. PMID 17775571.

[12] Kerek F (2000). "The structure of the digitalislike and natriuretic factors identified as macrocyclic derivatives of the inorganic carbon suboxide". Hypertension Research. 23 (Suppl S33): S33–38. doi:10.1291/hypres.23.Supplement_S33. PMID 11016817.

[13] Stimac R, Kerek F, Apell HJ (2003). "Macrocyclic carbon suboxide oligomers as potent inhibitors of the Na,K-ATPase". Ann. N. Y. Acad. Sci. 986: 327–329. doi:10.1111/j.1749-6632.2003.tb07204.x. PMID 12763840.

[14] Kerek F, Stimac R, Apell HJ, et al. (2002). "Characterization of the macrocyclic carbon suboxide factors as potent Na,K-ATPase and SR Ca-ATPase inhibitors". Biochimica et Biophysica Acta (BBA) - Biomembranes. 1567 (1–2): 213–220. doi:10.1016/S0005-2736(02)00609-0. PMID 12488055.

[15] Tubaro E (1966). "Carbon suboxide, the probable precursor of an antitumor cellular substance: retina". Bollettino Chimico Farmaceutico (in Italian). 105 (6): 415–416. PMID 6005012.

[16] Brown RD (1993). "Structural Information on Large Amplitude Motions". In Laane J, Dakkouri M, Veken Bv, et al. (eds.). Structures and Conformations of Non-Rigid Molecules. NATO ASI Series. 410. Springer Netherlands. pp. 99–112. doi:10.1007/978-94-011-2074-6_5. ISBN 9789401049207.

[17] Jensen P, Johns JW (1986). "The infrared spectrum of carbon suboxide in the ν6 fundamental region: Experimental observation and semirigid bender analysis". J. Mol. Spectrosc. 118 (1): 248–266. doi:10.1016/0022-2852(86)90239-0.

[18] Clark A (1970). "The potential function for the CCC bending in carbon suboxide". Chem. Phys. Lett. 6 (5): 452–456. doi:10.1016/0009-2614(70)85190-9.

[19] Ellern A, Drews T, Seppelt K (2001). "The Structure of Carbon Suboxide, C
3O
2, in the Solid State". Z. Anorg. Allg. Chem. 627 (1): 73–76. doi:10.1002/1521-3749(200101)627:1<73::aid-zaac73>3.0.co;2-a. ISSN 1521-3749.

[20] Frenking G, Tonner R (2009). "Divalent carbon(0) compounds". Pure Appl. Chem. 81 (4): 597–614. doi:10.1351/pac-con-08-11-03. ISSN 1365-3075. S2CID 98257123.

[21] Himmel D, Krossing I, Schnepf A (2014). "Dative Bonds in Main-Group Compounds: A Case for Fewer Arrows!". Angewandte Chemie International Edition. 53 (2): 370–374. doi:10.1002/anie.201300461. ISSN 1521-3773. PMID 24243854.

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show v t Oxocarbons
Common oxides	CO CO ₂
Exotic oxides	CO ₃ CO ₄ CO ₅ CO ₆ C ₂O C ₂O ₂ C ₂O ₃ C ₂O ₄ (1,2-Dioxetanedione and 1,3-Dioxetanedione) C ₃O C ₃O ₂ C ₃O ₃ C ₃O ₆ C ₄O ₂ C ₄O ₄ C ₄O ₆ C ₅O ₂ C ₅O ₅ C ₆O ₆ (Cyclohexanehexone and Ethylenetetracarboxylic dianhydride) C ₈O ₈ C ₉O ₉ C ₁₀O ₈ C ₁₀O ₁₀ C ₁₂O ₆ C ₁₂O ₉ C ₁₂O ₁₂
Polymers	Graphite oxide CO
Compounds derived from oxides	Metal carbonyls Carbonic acid Bicarbonates Carbonates Dicarbonates Tricarbonates

show v t Inorganic compounds of carbon and related ions
Compounds	CBr₄ CCl₄ CF CF₄ CI₄ CO CO₂ CO₃ CO₄ CO₅ CO₆ COS CS CS₂ CSe₂ C₃O₂ C₃S₂ SiC
Carbon ions	Carbides [:C≡C:]^2–, [::C::]^4–, [:C=C=C:]^4– Cyanides [:C≡N:]^– Cyanates [:O-C≡N:]^– Thiocyanates [:S-C≡N:]^– Fulminates [:C≡N-O:]^– Isothiocyanates [:C≡N-S:]^–
Oxides and related	Oxides Nitrides Metal carbonyls Carbonic acid Bicarbonates Carbonates

show v t Oxides
Mixed oxidation states	Antimony tetroxide (Sb₂O₄) Cobalt(II,III) oxide (Co₃O₄) Lead(II,IV) oxide (Pb₃O₄) Manganese(II,III) oxide (Mn₃O₄) Iron(II,III) oxide (Fe₃O₄) Silver(I,III) oxide (Ag₂O₂) Triuranium octoxide (U₃O₈) Carbon suboxide (C₃O₂) Mellitic anhydride (C₁₂O₉) Praseodymium(III,IV) oxide (Pr₆O₁₁) Terbium(III,IV) oxide (Tb₄O₇) Dichlorine pentoxide (Cl₂O₅)
+1 oxidation state	Copper(I) oxide (Cu₂O) Caesium oxide (Cs₂O) Dicarbon monoxide (C₂O) Dichlorine monoxide (Cl₂O) Gallium(I) oxide (Ga₂O) Lithium oxide (Li₂O) Potassium oxide (K₂O) Rubidium oxide (Rb₂O) Silver oxide (Ag₂O) Thallium(I) oxide (Tl₂O) Sodium oxide (Na₂O) Water (hydrogen oxide) (H₂O)
+2 oxidation state	Aluminium(II) oxide (AlO) Barium oxide (BaO) Beryllium oxide (BeO) Cadmium oxide (CdO) Calcium oxide (CaO) Carbon monoxide (CO) Chromium(II) oxide (CrO) Cobalt(II) oxide (CoO) Copper(II) oxide (CuO) Dinitrogen dioxide (N₂O₂) Germanium monoxide (GeO) Iron(II) oxide (FeO) Lead(II) oxide (PbO) Magnesium oxide (MgO) Manganese(II) oxide (MnO) Mercury(II) oxide (HgO) Nickel(II) oxide (NiO) Nitric oxide (NO) Palladium(II) oxide (PdO) Silicon monoxide (SiO) Strontium oxide (SrO) Sulfur monoxide (SO) Disulfur dioxide (S₂O₂) Thorium monoxide (ThO) Tin(II) oxide (SnO) Titanium(II) oxide (TiO) Vanadium(II) oxide (VO) Zinc oxide (ZnO)
+3 oxidation state	Actinium(III) oxide (Ac₂O₃) Aluminium oxide (Al₂O₃) Antimony trioxide (Sb₂O₃) Arsenic trioxide (As₂O₃) Bismuth(III) oxide (Bi₂O₃) Boron trioxide (B₂O₃) Cerium(III) oxide (Ce₂O₃) Chromium(III) oxide (Cr₂O₃) Cobalt(III) oxide (Co₂O₃) Dinitrogen trioxide (N₂O₃) Dysprosium(III) oxide (Dy₂O₃) Erbium(III) oxide (Er₂O₃) Europium(III) oxide (Eu₂O₃) Gadolinium(III) oxide (Gd₂O₃) Gallium(III) oxide (Ga₂O₃) Holmium(III) oxide (Ho₂O₃) Indium(III) oxide (In₂O₃) Iron(III) oxide (Fe₂O₃) Lanthanum oxide (La₂O₃) Lutetium(III) oxide (Lu₂O₃) Manganese(III) oxide (Mn₂O₃) Neodymium(III) oxide (Nd₂O₃) Nickel(III) oxide (Ni₂O₃) Phosphorus monoxide (PO) Phosphorus trioxide (P₄O₆) Praseodymium(III) oxide (Pr₂O₃) Promethium(III) oxide (Pm₂O₃) Rhodium(III) oxide (Rh₂O₃) Samarium(III) oxide (Sm₂O₃) Scandium oxide (Sc₂O₃) Terbium(III) oxide (Tb₂O₃) Thallium(III) oxide (Tl₂O₃) Thulium(III) oxide (Tm₂O₃) Titanium(III) oxide (Ti₂O₃) Tungsten(III) oxide (W₂O₃) Vanadium(III) oxide (V₂O₃) Ytterbium(III) oxide (Yb₂O₃) Yttrium(III) oxide (Y₂O₃)
+4 oxidation state	Americium dioxide (AmO₂) Carbon dioxide (CO₂) Carbon trioxide (CO₃) Cerium(IV) oxide (CeO₂) Chlorine dioxide (ClO₂) Chromium(IV) oxide (CrO₂) Dinitrogen tetroxide (N₂O₄) Germanium dioxide (GeO₂) Hafnium(IV) oxide (HfO₂) Lead dioxide (PbO₂) Manganese dioxide (MnO₂) Neptunium(IV) oxide (NpO₂) Nitrogen dioxide (NO₂) Osmium dioxide (OsO₂) Plutonium(IV) oxide (PuO₂) Praseodymium(IV) oxide (PrO₂) Protactinium(IV) oxide (PaO₂) Rhodium(IV) oxide (RhO₂) Ruthenium(IV) oxide (RuO₂) Selenium dioxide (SeO₂) Silicon dioxide (SiO₂) Sulfur dioxide (SO₂) Tellurium dioxide (TeO₂) Terbium(IV) oxide (TbO₂) Thorium dioxide (ThO₂) Tin dioxide (SnO₂) Titanium dioxide (TiO₂) Tungsten(IV) oxide (WO₂) Uranium dioxide (UO₂) Vanadium(IV) oxide (VO₂) Zirconium dioxide (ZrO₂)
+5 oxidation state	Antimony pentoxide (Sb₂O₅) Arsenic pentoxide (As₂O₅) Dinitrogen pentoxide (N₂O₅) Niobium pentoxide (Nb₂O₅) Phosphorus pentoxide (P₂O₅) Protactinium(V) oxide (Pa₂O₅) Tantalum pentoxide (Ta₂O₅) Vanadium(V) oxide (V₂O₅)
+6 oxidation state	Chromium trioxide (CrO₃) Molybdenum trioxide (MoO₃) Rhenium trioxide (ReO₃) Selenium trioxide (SeO₃) Sulfur trioxide (SO₃) Tellurium trioxide (TeO₃) Tungsten trioxide (WO₃) Uranium trioxide (UO₃) Xenon trioxide (XeO₃)
+7 oxidation state	Dichlorine heptoxide (Cl₂O₇) Manganese heptoxide (Mn₂O₇) Rhenium(VII) oxide (Re₂O₇) Technetium(VII) oxide (Tc₂O₇)
+8 oxidation state	Osmium tetroxide (OsO₄) Ruthenium tetroxide (RuO₄) Xenon tetroxide (XeO₄) Iridium tetroxide (IrO₄)
Related	Oxocarbon Suboxide Oxyanion Ozonide Peroxide Superoxide Oxypnictide
Oxides are sorted by oxidation state. Category:Oxides

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